New study finds that marijuana can reprogram sperm genes

We already know that cannabis lowers sperm count, but new research suggests that the drug actually causes genetic changes to the sperm itself — which might have implications for the health of a potential baby.

For a study published today in the journal Epigenetics, scientists at Duke University

Think of your DNA as a list of instructions for making proteins, and genes as small subsets of that list. Our body has little chemical tags (called methyl groups) that get added to the DNA at specific regions, explains Susan Kay Murphy, a professor of gynecology at Duke and co-author of the study. These chemicals don’t mutate the genes themselves, but they do affect how they’re used, like deciding which instructions are followed and which aren’t.

Najari already counsels men who use marijuana regularly to cut back because of the effect on sperm count. “I think one of the important positive things about research like this is that it may further motivate men to change their health,” he adds. “It’s one thing to talk about sperm count, another when you’re talking about the potential health of the child.”

Both Najari and Murphy stress that future research needs to be done, and the Duke team is already working on follow-up studies. Are those changes reversible? Will they even end up affecting a potential baby? “